The present invention is directed to medical treatments for fibromyalgia and related conditions. Specifically, the invention is directed to the administration of the drug flupirtine as a means for alleviating the symptoms associated with these disorders.
Fibromyalgia is a chronic condition characterized by pain in muscles, fascia and joints. Other symptoms typically include sleep disturbances, chronic fatigue and major depression. The etiology and pathophysiology of fibromyalgia are unknown, but it is clear that the central nervous system is involved. Patients may obtain a degree of relief from analgesic drugs, antidepressants and adjunctive treatments such as moderate exercise, proper diet and stress reduction techniques. Table 1 summarizes the studies that have been carried out in an effort to find an effective drug treatment.
Despite the efforts that have been made, there is still no treatment that is effective in the majority of patients with fibromyalgia. Thus, there is a clear need for new therapies designed to alleviate the suffering of patients with this, and closely related, conditions.
Flupirtine is an analgesic that has been used in Europe to treat the pain associated with surgery, cancer, trauma, and liver disease. It acts via the central nervous system through non-opite pain pathways, possibly involving the thalamus or spinal pain pathways. In some, but not all, studies flupirtine has been found to be as effective as opiates in relieving pain. Moreover, flupirtine offers a clear advantage over opiates in that it is not addictive and there have been no reports of abuse. The present invention is based upon the unexpected discovery that flupirtine is capable of completely eliminating the chronic and severe body pain present in some patients with fibromyalgia. Relief is possible even when high doses of opiates, non-steroidal anti-inflammatory drugs and placquenil fail to alleviate pain.
In its first aspect, the invention is directed to a method of treating a patient with fibromyalgia by administering a pharmaceutical composition containing flupirtine. The dosage of flupirtine should be sufficient to reduce or eliminate one or more of the symptoms that have been associated with fibromyalgia. These symptoms include diffuse musculoskeletal pain, fatigue, ocular and vestibular disturbances, headaches, paresthesias, esophageal dysmotility, sleep disturbances, and severe depression. The flupirtine may be administered in any dosage form including tablets, capsules, gels, or topical preparations and should be given at a daily dosage of between 50 and 900 mg, calculated on the basis of the free base form of the drug. In general, dosage should not exceed 600 mg per day and the optimal range should typically be between 100 and 400 mg per day. The flupirtine may be administered in either a single or, preferably, multidosage daily regimen.
In addition, the present invention is directed to methods of treating a patient for diseases or conditions that are related to fibromyalgia by administering flupirtine. Again, the dosage should be between 50 and 900 mg per day, calculated on the basis of the free base form of the drug, and should preferably be between 100 and 400 mg per day. The flupirtine may be given in any dosage form and administration may be accomplished by any route. Specific diseases that are defined as being related to fibromyalgia include fibrositis; chronic fatigue syndrome; myofascial pain syndrome, soft tissue rheumatism; idiopathic muscle pain syndrome; chronic widespread musculoskeletal pain; major depression associated with musculoskeletal pain; somatization disorder; somatoform pain disorder; Lyme disease with concurrent fibromyalgia; rheumatoid arthritis with concurrent fibromyalgia; generalized tendomyopathy; eosinophilia-myalgia syndrome; and stiff-man syndrome.